Payments to addresses that start with a “z” are definitely broken as you can read in the following threads:
Github: unconfirmed transactions · Issue #1705 · zcash/zcash · GitHub
Forum: ZCash Desktop GUI Wallet - #52 by cryptomined
Unfortunately there is nothing we can do at the moment as we need to wait for the Zcash developers to fix the issue.
Regarding payments to “t” addresses our payment processor was overloaded and was unable to keep up with the payment requests. We have increased its capacity and payments should be issued in a more timely fashion now.
We can assure you we are working hard to keep the pool operating and the payouts running. Which is not an easy task given the low maturity of the Zcash software.